Portable fluorescence instrument

Abstract

A portable fluorescence instrument characterized by ultraviolet excitation optics and fluorescence spectral optics, particularly adapted for analysis of oil samples. The excitation optics include circuitry that adapts the instrument for field exploration by using low voltage power obtainable either from an internal rechargeable power source or from a conventional power source or from a conventional automobile battery. The fluorescence optics include a density step tablet that modulates the fluorescence intensity resulting in a spectral display characteristic of the particular sample. The spectral display is recorded on an instant film for on-site analysis.

What is claimed is: 
     
       1. A portable fluorescence instrument contained within a casing and comprising: (a) a source for generating radiation in a first path;   (b) a sample chamber to present samples into said first path;   (c) a shutter disposed in said first path between said source and said sample chamber;   (d) said samples, when excited by said radiation from said source, emitting fluorescent radiation in a second path;   (e) a grating having a focal plane off the Rowland circle and disposed in said second path for dispersing said fluorescent radiation;   (f) first means disposed in said second path between said sample chamber and said grating to modulate the intensity of said fluorescent radiation striking said grating; and   (g) second means disposed in said focal plane of said grating off said Rowland circle to record the modulated radiation dispersed by said grating.   
     
     
       2. A portable fluorescence instrument contained within a casing and comprising: (a) a source for generating radiation in a first path;   (b) a sample chamber to present samples into said first path;   (c) a shutter disposed in said first path between said source and said sample chamber;   (d) said samples, when excited by said radiation from said source, emitting fluorescent radiation in a second path;   (e) a grating disposed in said second path for dispersing said fluorescent radiation;   (f) first means disposed in said second path between said sample chamber and said grating to modulate said fluorescent radiation striking said grating, said first means being a neutral density step filter comprising a substrate having a plurality of steps, with said steps characterized by possessing linearly attenuated densities as between said steps; and   (g) second means disposed in the focal plane of said grating to record the modulated radiation dispersed by said grating.   
     
     
       3. The portable fluorescence instrument of claim 2 wherein said attenuation in the densities of said steps is effected by evaporating varying amounts, as between steps, of a nickel-base alloy containing about 16% chromium and about 7% iron on said substrate. 
     
     
       4. The portable fluorescence instrument of claim 1 further including a second shutter, disposed in said second path, said first and second shutters being operated in synchronism, and wherein said second means is an instant film. 
     
     
       5. The portable fluorescence instrument of claim 4 further including a low voltage internal rechargeable power source and an adaptor to a low voltage external power source, with either source being sufficient to power said radiation source. 
     
     
       6. A portable, self-contained fluorescence instrument comprising: (a) a casing having a body portion, a cover portion and a handle secured to said body portion, said body portion having a panel facing said cover portion, said body portion removably accommodating the operative parts of said instrument behind said panel;   (b) a lamp emitting ultraviolet radiation in a first path;   (c) a shutter disposed in said first path to permit passage of said ultraviolet radiation;   (d) a sample chamber designed to present samples into said first path;   (e) said samples, upon being excited by said ultraviolet radiation, emitting fluorescent radiation in a second path;   (f) a slit and a grating disposed in said second path, said grating for dispersing said fluorescent radiation;   (g) a neutral density step filter disposed in said second path between said sample chamber and said slit to modulate said fluorescent radiation entering said slit; and   (h) means disposed in the focal plane of said grating to record the radiation dispersed by said grating.   
     
     
       7. The portable, self-contained fluorescence instrument of claim 6 wherein said grating is a flat-field, holographic grating, substantially free of aberration and astigmatism and having a focal plane off the Rowland circle. 
     
     
       8. The portable, self-contained fluorescence instrument of claim 6 wherein said body portion is provided with a light-tight compartment. 
     
     
       9. An optical system for use in a fluorescence instrument, said system comprising: (a) excitation optics including a radiation source, circuitry having a low voltage portable power source to power said radiation source, and a filter to filter the radiation from said radiation source;   (b) means to present a sample into the path of said radiation from said radiation source to excite said sample to fluoresce in a second path; and   (c) fluorescence optics disposed in said second path and including a density step tablet to modulate the fluorescent radiation emanating from said sample.   
     
     
       10. The optical system of claim 9 wherein said radiation source is a low pressure mercury lamp. 
     
     
       11. The optical system of claim 9 wherein said density step tablet is a neutral density step filter comprising a substrate having a plurality of steps, with said steps characterized by possessing linearly attenuated densities as between said steps. 
     
     
       12. The optical system of claim 11 wherein said attenuation in the densities of said steps is effected by evaporating varying amounts, as between said steps, of a nickel-base alloy containing about 16% chromium and about 7% iron on said substrate.